In general, a semiconductor wafer prober station is one of electrical die sorting (EDS) test equipments used in a semiconductor manufacturing process to electrically test whether or not dies in wafer states can normally operate and detect defects of the dies by contacting probes to the dies in the semiconductor wafers and applying electrical signals thereto before packaging semiconductor chips formed on the semiconductor wafers. The aforementioned wafer prober is a manufacturing equipment for directly contacting and testing a pad of a die formed on a wafer to remove a defective die early and reducing losses of raw materials, time, and the like used in the following packaging and packaging test processes.
FIG. 1 is a front view illustrating a wafer prober station. Referring to FIG. 1, the wafer prober station includes a wafer loader for transferring a semiconductor wafer at a position on a FOUP or a cassette to be tested or on a chuck, a stage for precisely transferring the wafer to contact the wafer to a probe card to be tested, and a tester for testing the wafer disposed on the chuck on the stage. A header of the tester is mounted with the probe card and applies an electrical signal to the die on the wafer by using the probe card to measure the result and detect defects of each die.
The stage of the wafer prober station needs to be precisely controlled in x, y, and z directions. The stage is basically formed in a straight direction. However, the stage may be physically deteriorated in units of micron that is a control unit of the stage. In addition, operations of the stage have to be controlled in units of micron. However, due errors of a control encoder mounted at both sides of the stage, precise control is not easy. In addition, in a case where the stage has been operated for a long period or applied with an external impact, precision of the stage is easily decreased.
As described above, in order to measure a degree of the physical deterioration of the stage and calibrate the stage with physical deterioration, a laser measuring method is conventionally used. However, since a laser measurer used in the laser measuring method is a device sensitive to surroundings, in order to calibrate the stage, an additional repairing space having a predetermined condition is needed, and parts of the wafer prober system have to be disassembled, so that calibration takes much time. Therefore, when problems occur while using devices, the devices have to be transferred to the additional repairing space so as to be repaired, so that additional costs and time are needed.
Therefore, it is proposed a device which can reduce a time to measure errors that occur due to the deterioration of the stage and have a simple structure to be easily transferred and stored.